In the production of footwear, a technique to allow a plurality of members different in chemical properties or mechanical properties from each other to adhere to each other is important. In particular, in the production of sports shoes undergoing strong stress during use, a technique allowing the constitutional members of sports shoes to strongly adhere to each other is required. As an adhesion technique developing such strong adhesiveness, there has hitherto been a method in which the individual constitutional members are, if necessary, beforehand subjected to treatments such as degreasing, buffing and primer coating, then coated with an adhesive, and allowed to adhere to each other through the intermediary of the adhesive. Among these treatments before the coating of the adhesive, the primer coating assumes a significant role with respect to the adhesiveness between the footwear constituting members and the adhesive, and plays an important role as the adhesion technique for footwear.
Sports shoes are always required to achieve high functionalization in, for example, various performances such as cushioning property, lightweighting and design. In order to cope with the need for such high functionalization, novel materials have been proposed day after day for the constitutional members of footwear. Naturally, when such novel materials are used for the constitutional members of footwear, a high level adhesion technique is required. However, even when such novel materials are proposed, no sufficient adhesiveness is obtained by using conventional primers, and hence practical use of such novel materials is sometimes impossible. In other words, novel materials simultaneously require primers compatible therewith.
For the purpose of being adapted to such novel materials, primers for footwear have been proposed in Patent Literature 1 and Patent Literature 2.